Re: Revising Hou et al, 96 (woo-o-o-o-o-o-o doggy!)

["Jaime A. Headden" <qilongia@yahoo.com>]

  This combines with my previous response on *Avimimus* features.

Mickey Mortimer (Mickey_Mortimer111@msn.com) wrote:

<The size of the foramen is caused more by the precise articulation of the
quadrate, which is more anterior in Dromaeosaurus (the posterior process
extends past the mandibular portion of the quadrate in Dromaeosaurus, but
doesn't even reach the posterior edge in Velociraptor).>

  Actually, the foramen is opened by the dorsal process on the lateral
margin of the quadrate, which is usually triangular in aspect. The size of
this process and its width indicates how much the quadratojugal is
positioned rostrally. This is apparent in *Bambiraptor*, *Velociraptor*,
and *Dromaeosaurus*.

<Keep in mind Dromaeosaurus' quadratojugal also has a bowed dorsal process
which is placed at about the halfway point of the ventral margin. 
Deinonychus may very well have an enlarged foramen, but we don't yet have
the data to determine this for sure.>

  Fair enough.

<No, I said Rahonavis has the "pes construction (an apparent troodontid +
dromaeosaurid synapomorphy, along with pedal digit II features)" that you
said was evidence for placing Microraptor in the Deinonychosauria.>

  I was refering to the caudal flanges on the metatarsus, which was my
very previous paragraph. What were _you_ thinking of (not to be taken
insultingly -- change the accent on the next word and this could be
fightin' words...)?

<You may be correct regarding Gallimimus, as the reconstructed premaxilla
doesn't look like other ornithomimids (but Paul's reconstruction does).>

  Paul doesn't add a whole lot to the front of *Gallimimus* snout, but
that's okay. As for ornithomimids (and the other taxa), I was measuring
the subnarial hieght versus length, not the total premax height, which may
be functionally deformed due to external narial shape and size, and I do
not think this is a valid reason to use the whole premaxillary height.
True elongation of the premax may only be valid as a ratio to skull length
or maxilla length. I have not measured ratios on this score.
  
<What you failed to mention was that Sinornithosaurus' premaxilla is over
four times as long as it is deep, much more than most other non-avian
coelurosaurs (the exceptions being Compsognathus, ornithomimosaurs and
Shuvuuia).  My exact character is "length of premaxillary ventral edge
more than 250% the minimum height of the premaxilla under naris".  I stand
by my assertion this is a possible avialan character of Sinornithosaurus.>

  When *Archaeopteryx* has a shorter premaxilla (only three times longer)
and *Confuciusornis* and other birds tend to have modified beaks to begin
with, and that on this basis higher birds must have had to lengthen the
premaxilla, this is convergent.

<Looking over the distribution of this character, it's actually more
parsimonious to have serrationless premaxillary teeth be basal for most
coelurosaurs (perhaps excluding tyrannosauroids) and reversing in
Scipionyx, Protarchaeopteryx, derived troodontids and dromaeosaurids.>

  Show me an instance of a tooth developing serrations in a lineage with
several ancestors with teeth lacking the conditions (besides fish). And
before you say crocodiles, serrations are the plesiomorphic condition and
embryologically, crocs can have or not have any serrations. These are
distinctly linked to a predatory diet, and the tearing of flesh, and the
condition of loss of serrations is the functional direction that is diet
related. Animals that loose serrations and redevelope a tearing lifestyle
(birds) do so with modifications of the existing anatomy, as in forming
extra cusps (mammals), angling the teeth (fish), or modifying the edge of
the jaws in case of tooth loss (ornithomimids, oviraptorids,
*Caudipteryx*, and several birds including rhamphastid piciforms and
raptorial birds). This is where the cladistic machine cannot explain the
true nature of a functional loss in a dietary condition, such as
serrations which are present embryologically or during enamel build-up
during very early ontogeny. It is easier then to say that loss of
serrations is the convergent condition, but this is no more parsimonious
and the character should be removed from cladistic matrices.

<You mean the squamosals that Xu and Wu identify questionably enough not
to discuss them in the text (one of which was originally identified as a
prefrontal)?  The ascending process is near certainly not longer than
presented in figure 4E, as the amount of tapering indicates the preserved
base connected within a millimeter of the broken area on the main
quadratojugal body.>

  I lack that paper, but that's okay. I reconstruct the skull as I see the
material in photos, not from Xu et al's figures. Sorry. My ID of the
squamosal is based on general shape and the multi-ramal nature of the
element.

<Fine, I'll use the femoral length as a reference.  Sinornithosaurus has
sterna 57% of femoral length, while Velociraptor has a ratio of 48%. Then
again, I never said sternal size was an avialan synapomorphy of
Sinornithosaurus, just the amount of sternal ribs.  Xu et al. (1999)
specifically state "its constricted anterolateral side bears a series of
posdsible five rib attachments".  Velociraptor and Citipati have three.>

  And how many does *Archaeopteryx*, *Unenlagia* and *Rahonavis* have? And
actually, you did say that the length of the sterna were evident of rib
count. *Confuciusornis* definately has five (they are preserved in
multiple specimens, not just trying to count rib facets [facets are not
clearly evident in *Confuciusornis* sternae]).

<Notice that not only is Velociraptor's furcula thinner than either
Sinornithosaurus or Archaeopteryx, it has the small hypocleidium and the
arms each have a convex inside edge, completely unlike the furculae of the
other two genera, which have concave internal edges.>

  I think my point was that the furcula was transistory between the two,
which would, under my end-point last post, have a variable effect on
phylogeny... *Sinornithosaurus* is still intermediate between the "avian"
and the "dromaeosaurid" conditions.

<How are many taxa and a list of vales then?  See a clear increase in
fibular width (as a percentage of tibial width; on right in parentheses)
with increasing size (represented by femoral length to left)?  I don't.>

  I thought I covered this at the end of the post. Robusticity indexes and
neoterrestrial structures are expected. Trying to use them to explain
avialian conditions is going to fall flat if these appear to be related to
cursoriality and scansoriality. Tree-huggers have delicate limbs, walkers
don't. Once the deinonychosaurs hit the ground, they required and increase
in the robusticity to effect their larger size. *Comspognathus* was not so
fortunate as no theory currently puts it into a guild where its direct
ancestors were arboreal, as in Xu et al.s theory.

<Which quadrate of Microvenator would you be referring to?  The unknown
one? ;-)  (rhetoric good :-)  )>

  I think I specifically refered to a mandible, not a quadrate, and that
was of *Microraptor* (damn names...). Please be civil (I've asked before,
but this didn't help).

<The shaft.  Paul actually used this quite prominently in his SVP
presentation,>

  ... which I didn't attend ...

<it's easier to see in cf. Sinornithosaurus.  Archaeopteryx probably does
lack it.  That's why it's in the "characters also found in more derived
birds, but not Archaeopteryx" section of my list.  Again with the unknown
Microvenator elements.>

  ... which I never mentioned ...

<Perhaps you mean Microraptor, but phalanx II-I isn't known in that genus
either.  Could you be referring to the new skeletons (have an early copy
of the new AMN paper perhaps)?>

  Ah wonderful ...  see above about the Micro-dino names. It's not pdII-1
that's nessesary for evaluation of the heel, however, it's pdII-2.
Conversely, this may also indicate the presence of the greater arc on the
distal pdII-1, but that's not really the point.

<Please... accuracy.>

  You shouldn't have jumped to conclusions when I said that. Ask
questions.

<The shaft has a distinct 40 degree kink about 60% down the shaft,
expanding slightly after the halfway point.>

  You say kink, I say curvature ... let's call the whole thing off. I feel
link singin' ...

  "No laetha geal m'oige..."

<This is not at all like the "J-shaped" pubis noted in Unenlagia for
instance, which is straight except for the large foot, which is directed
posterodorsally.>

  Unlike *Sinovenator* and *Rahonavis,* which curve approximately at the
midlength of the bone, or *Archaeopteryx* and *Velociraptor* which are
actually slighly concave along the cranial margin, along with "basal"
*Achillobator*, or *Deinonychus* (more straight like *Mononykus* and
*Shuvuuia* and *Parvicursor*).

<Sinornithosaurus has no abrupt expansion to indicate the presence of a
pubic foot.>

  So it has to be abrupt to be a pubic foot? I was under the impression,
as in cros pubes, that the expansion towards the distal end is a
_degenerate_ condition from a projecting boot, but that it qualifies,
nonetheless. When I used the term "J-shaped" (as I clarified last post, so
it should not be a problem now) it was the curvature of the shaft. I, as
did Pete Buchholz last year, refer to the pubes of [only] *Archaeopteryx*,
*Rahonavis*, and *Unenlagia* as "hooked" in lateral aspect.
*Sinorinithosaurus* lacks a projection, *Microraptor* presently lacks a
pubis, *Sinovenator* is more distinctly expanded caudally, and
velociraptorine pubes are similar to *Sinovenator* in projecting caudally
without the "hooked" profile, and unlike *Achillobator* which is more
"carnosaur"-like in aspect with a distinct cranial expansion.

<Sinovenator has at least a small posterior expansion (possibly broken)>

  You see something I do not, as the cranial margin appears to flow from
the midpoint ventrally and curve caudally without deviation. I have not
seen the pubis of "Troodon" but that of *Saurornithoides* lacks a boot
almost entirely but with a small caudal component.

<Pedal phalanx II-2 is missing in Ornitholestes (Ostrom, 1969), so the
state is unknown.>

  My mistake. My erroneous source. Anyway...

<What are your mysterious "other taxa"?>

  Actually, given the morphology of the heel in some troodontid pes and
one dromaeosaur pes in my view, including *Microraptor*, *Borogovia* is
marginalized and the pes of *Avimimus* and mononykines have this. There
was another taxon but for some reason I can't find it. I keep thinking
enantiornithine, but I may be wrong. It's absent in perching birds, so no
go.

<Sounds to me like it was intended to provide evidence Sinornithosaurus is
a deinonychosaur, and not an avialan.>

  Uhm ... yeah? And I said that to begin with, did I not? I suggested also
that the alternate phylogeny of Xu et al. retains these features, but that
my concept was to consider _that_ (as I actually said).

<Which is why I don't understand why you would be trying to prove its
existance in other taxa now.  _My_ side in this debate is that these
"deinonychosaurian" characters are plesiomorphic for eumaniraptorans or
eumaniraptorans + troodontids.>

  Both may be equally parsimonious. Lack of your inclusion of
*Sinovenator* may be clouding your matrix. However, it would appear that
the polarization it offers that the robust consideration is as I have laid
out. How long have I been saying that these last few days?

<Ornitholestes' second pedal ungual is also too poorly preserved to
indicate whether it has a raptorial morphology (Ostrom, 1969 again).>

  From the photos of the wall mount I've seen, it is quite recurved. Maybe
plaster....

<Of course, that would support my position that they are troodontid +
eumaniraptoran plesiomorphies.>

  No it wouldn't. It would say it would be in birds, too. You';d have to
support the presence in _basal-most_ birds to make your contention work.
Plesiomorphic to Avialae is the root that bears the claws and pedal
specializations, shoulder and hip morphology, and skull features, which
can be considered easily as closely-associated features that permitted
Archie flight and the deinonychosaurs a secondary terrestrial existence
from basal arboreals (in this scenario, *Sinornithosaurus*, *Microraptor*,
and possibly *Sinovenator* [but it's arms may be too short]). This theory
is not impractical, and in fact appears to agree with development of
integument, among other things (including possible loss of pinnate
feathers as in ratites).

<Paul (DA) explicitly describes its presence in Archaeopteryx.>

  Looking at several posterior and lateral/medial views of several
*Archaeopteryx* specimens, I most certainly disagree with this.

<Certainly there's no way you can refute it without actually seeing the
specimen.>

  In *Rahonavis*, there are materials to permit easy access in this
manner, but in *Archaeopteryx*, without dislocated metatarsals and that
book, I have no way to determine Paul's evidence. However, I will see the
book at the end of next week anyway, so there should be no problem with
this.

  Once again, I reiterate the plausibility to determine either a
archie-first or birds-higher-than-thou theory in the development or loss
of many so-called flight-related features. Your refutation appears to be
based on features that I myself can simply reverse in reference to Xu's
phylogeny and find the opposite development. This makes me think that an
evolution towards flight is a common preferrence or theme in some
perspectives, and it may be yours, but I take a much more mechanical view
and can easily see the loss of such structures as a mere flick of the
avian wrist, to make magically the polarity at the base of
Paraves/Eumaniraptora turn from flight to flightless, or vice versa.

=====
Jaime A. Headden

  Little steps are often the hardest to take.  We are too used to making leaps 
in the face of adversity, that a simple skip is so hard to do.  We should all 
learn to walk soft, walk small, see the world around us rather than zoom by it.

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